1. Field of the Invention
This invention relates to a growing medium container designed to permit plants such as nursery stock to be grown in their early developmental stages above ground, and to permit vegetable and fruit crops to be grown over their entire life-cycle duration. The invention also relates to the process of forming the container, as well as the process for growing the plants for a limited time above ground and later transplanting the plants into the soil.
2. Description Of The Prior Art
The growing of nursery stock, such as trees, shrubs and other vegetation, especially outdoor plants, in containers during their early stages of development is widely known. Early transplanting bags designed essentially to contain the "earth balls" surrounding the roots of nursery stock for transplanting purposes are disclosed in, for example, U.S. Pat. No. 2,796,700 to Katz, and U.S. Pat. No. 3,550,662 to Remke, et al. These transplanting bags are generally designed to not only contain the earth balls after the plant has been dug from the soil, but also to ensure that the roots system is kept moist and free from damage. Other containers for plant growth and cultivation are disclosed in U.S. Pat. No. 4,209,945 to Dent, et al. and U.S. Pat. No. 4,369,599 to Franclet, et al. The growing of plant stock in-ground and later removing the plant from the ground, bagging the root ball and shipping the plant to be transplanted has many disadvantages. The process is extremely labor intensive. As the plant is removed from the ground, sufficient root structure and earth surrounding the roots must be retained, otherwise the plant may be severely shocked. Further, since the roots are not contained, large roots must be cut which unavoidably causes damage and shocks the plant.
In order to overcome some of these disadvantages of in-ground growing of nursery stock, in-ground growing methods have been developed to contain the developmental growth of the root structure to a specific area. For example, U.S. Pat. No. 4,884,367 to Lawton discloses a root control bag used to contain the roots of plant stock during in-ground cultivation prior to later excavation and transplantation after the plant has reached a desired stage of maturation. Similarly, U.S. Pat. No. 4,574,522 to Reiger, et al. and U.S. Pat. No. 4,888,914 to Reiger disclose a root control bag and a method for root control, respectively, for controlling root growth of nursery stock planted in the ground prior to transplanting. These patents disclose excavating a hole in the ground, lining the hole with a non-woven, porous polymeric fabric bag, inserting a plant with root ball and filling earth around the in-ground planting. When the plant has reached its desired stage of maturation, the plant is then dug out and shipped for transplanting. Even though this method and apparatus alleges to constrict the roots sufficiently to produce nodule root formation and root branching within the container, this method of in-ground cultivation nevertheless has many of the same disadvantages of prior in-ground cultivation techniques. The removal of the plant from an in-ground plot is still labor intensive. Even though it is alleged that not as many roots must be cut because of the use of the non-woven, polymeric bag, the plant still must be dug from the ground requiring much labor and resulting in some root damage. In large in-ground cultivation operations, expensive machinery is usually purchased in order to remove the plantings from the ground.
It is also known in the prior art to grow nursery stock during its early developmental stages above ground in non-porous, plastic side wall containers. The physical properties of these containers dictate not only their size and shape but also the growing medium that can be used. These conventional plastic containers must be shaped to be tall without having a large lower section. This shape is necessitated because of the poor drainage permitted by these containers. This shape causes container handling problems and leads to these containers turning over causing plant damage. Further the poor drainage caused by the containers necessitates that only very open and well drained growing medium can be used. This type of medium causes fertilization and irrigation problems. These tall plastic containers were developed to overcome the problems caused by short, non-porous containers which exagerate the problem of waterlogged soil. The excessive perched water table of capillary water in these prior art containers cannot drain from the container, and the roots quickly die. Further these prior art containers adversely effect heat transfer from the ground to the growing medium, which adversely affects root development.